1. Field of the Invention
The present invention relates to a valve for aromatic products, or products that develop fragrant gases, particularly powder-like products such as coffee and the like, packaged in air-tight containers. Specific reference will be made hereafter to coffee, it being understood that what is said applies in general to all those products that develop fragrant gases.
2. Discussion of the Background
Valves of the above mentioned type are obviously already known and are commonly called degassing valves. They are one-way valves that are normally applied to the upper wall of the container and whose purpose it is to allow the gases developed by the coffee to escape from the container--thus avoiding the possible build-up of internal overpressures which would cause swelling and/or breakage of the container itself--and at the same time to prevent air from entering the container as this would impair the quality of the product.
The one-way valves used at present serve this purpose perfectly, opening when slight internal overpressures occur and closing immediately when they cease.
However, these valves present great drawbacks due to the following considerations.
Fresh (newly packaged) coffee generates a mixture of gases inside the container, consisting mainly of carbon dioxide and, a smaller percentage of aromas, which are characterized by complex molecular chains and thus have a high molecular weight.
The one-way valves currently used employ porous filters, whose sole purpose is to prevent the escape of coffee grounds (i.e. solid components of the coffee). In the event of overpressure inside the container, therefore, they allow both carbon dioxide and the product's aromas to escape through the valve.